An electroconductive polymer such as polyaniline, polypyrrole and polythiophene is expected to be applied in various fields as a performance material because the polymer has properties such as redox properties (oxidation-reduction properties) or doping and dedoping properties. The materials are formed into a nanosized material to take advantage of electroconductivity thereof, and thus are expected to be utilized in various applications such as a field emission material to be used for a field emission device in a field emission display (FED), a wiring material, a sensor, an electrochemical capacitor, a probe for a prove microscope and a catalyst carrier.
As for a nanosized electroconductive polymer, such an art is known as a method for producing a nanosized electroconductive polymer of polypyrrole and polythiophene according to an electrochemical technique using a nanocylinder (see Patent literature No. 1, for example). However, the method is unsuitable for mass production due to use of a supercritical fluid or subcritical fluid as an electrolytic solvent to complicate equipment and increase cost. Moreover, in the case where the method is employed, the method has involved problems of complicating a process also from necessity of removing a template, and a further increase in cost due to only one-time use of the template.
A carbon nanotube or a metal nanowire has been found in recent years to take a growing interest in an electroconductive nanomaterial. A nanomaterial having an average diameter in the range of several nanometers to several hundred nanometers and an average length of approximately 1 micrometer or more has been used in an application such as an electroconductive material, an electron emission device and the template for the carbon nanotube. As a method for producing the nanomaterial of the electroconductive polymer, only a method using the nanocylinder or the template as also described in Patent literature No. 1 has been known so far.
On the other hand, carbazole is a heterocyclic compound represented by a molecular formula: C12H9N, and is a compound having electroconductivity. An art is known in which N-alkylcarbazole as a derivative of carbazole can be formed into a performance compound for LED by allowing N-alkylcarbazole to react with cellulose in a solvent (see Patent literature No. 2, for example).
Then, the inventors of the invention have succeeded in polymerization of N-alkylcarbazole, and have proposed that poly(N-alkylcarbazole) can be provided as a transparent membrane structure (see Patent literature No. 3).